What is Keratoconus?

Have you wondered What is Keratoconus?

The textbook definition of keratoconus is a bilateral progressive asymmetric non-infective non-inflammatory degeneration of the cornea. What that means is that keratoconus is a disease that over time affects both eyes (one more intensively than the other), that is not caused by an infection or inflammation of the eye, and leads to the decay of the cornea. But why care what happens to the cornea?

Reasons you need to be aware What is Keratoconus?

There are three main reasons why you should care. The first is that the cornea acts as the first layer of protection, like a castle wall, for your eye preventing physical (sand, dust, dirt), microbiological (bacteria, viruses), chemical (pool water, seawater), and radiation (UV light) hazards from reaching deeper parts of the eye.

The second reason is that it needs to withstand the natural pressures of the eye. The pressure is created by fluids that are constantly moving in deeper parts of the eye. Think about it like filling a balloon with jelly; as the jelly moves and shakes it causes the balloon to expand in order to prevent the jelly from stretching it too thin, and since the cornea’s first job is to defend if it gets stretched the strength of the barrier weakens as well.

The third reason is the cornea helps in letting you see the world around you. As the light enters your eye the cornea actually bends all the scattering light rays into a single dense ray that it directs through the pupil, effectively focusing the image you see about 75%. Now for example if the cornea is stretched or blocked by dirt that immediately reduces the ability of you being able to see a clear image.

Since keratoconus weakens the cornea over time it affects the ability of the eye to perform its job properly which is to let you see the world around you, and as the cornea weakens in its ability to do its three main jobs it leads to a rapid loss of vision: even to the point where glasses and contacts would not be able to help in correcting the vision.

So what does keratoconus actually do to the cornea? Essentially it breaks the bonds that hold the cornea together. Think about what termites do with wooden walls. They weaken the wall from the inside and create hollow spaces that reduces the structural integrity, the same basically happens with the cornea, and once it starts its rate of deterioration is uncertain. So while the cornea still appears to be intact from the outside the inside is straining to hold itself together: how does this affect the cornea in doing its job?

The stretching greatly reduces the cornea’s ability to defend the eye from external factors (that were previously mentioned). This leads to the eye becoming more prone to infections because the wall has lost its ability to resist the oncoming enemies since it is more like wood than stone. This also leads to the eye becoming more susceptible to scarring, from objects like contacts for example, because the corneas’ ability to heal when objects scratch/touch it is greatly decreased.

The main problem a cornea with keratoconus is the stretching it primarily undergoes because it does not have the strength to hold the pressure of the eye at its required level. This causes the cornea to bulge or expand forward, like our example about a balloon full of jelly, and then gravity pulls it down further which leads to the cornea becoming cone shaped because the pressure is trying to leave through the apex of the cornea.

After all of this the ability for the cornea to do its third job of focusing the light is greatly reduced because like a telescope everything has to line up properly for it send messages accurately to the brain.


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